﻿Shader "UI/RectGuide"
{
    Properties
    {
        [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
        _Color ("Tint", Color) = (1,1,1,1)

        _RADIUS("radius",Range(0,0.5))=0.2
        //_Range ("range", range(0,1)) = 0.5

        _StencilComp ("Stencil Comparison", Float) = 8
        _Stencil ("Stencil ID", Float) = 0
        _StencilOp ("Stencil Operation", Float) = 0
        _StencilWriteMask ("Stencil Write Mask", Float) = 255
        _StencilReadMask ("Stencil Read Mask", Float) = 255

        _ColorMask ("Color Mask", Float) = 15

        [Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip ("Use Alpha Clip", Float) = 0

        _Center("Center",vector) = (0,0,0,0)
        _SliderX("SliderX",Range(0,1500)) = 1500
        _SliderY("SliderY",Range(0,1500)) = 1500
    }

    SubShader
    {
        Tags
        {
            "Queue"="Transparent"
            "IgnoreProjector"="True"
            "RenderType"="Transparent"
            "PreviewType"="Plane"
            "CanUseSpriteAtlas"="True"
        }

        Stencil
        {
            Ref [_Stencil]
            Comp [_StencilComp]
            Pass [_StencilOp]
            ReadMask [_StencilReadMask]
            WriteMask [_StencilWriteMask]
        }

        Cull Off
        Lighting Off
        ZWrite Off
        ZTest [unity_GUIZTestMode]
        Blend SrcAlpha OneMinusSrcAlpha
        ColorMask [_ColorMask]

        Pass
        {
            Name "Default"
        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma target 2.0

            #include "UnityCG.cginc"
            #include "UnityUI.cginc"

            #pragma multi_compile __ UNITY_UI_CLIP_RECT
            #pragma multi_compile __ UNITY_UI_ALPHACLIP

            struct appdata_t
            {
                float4 vertex   : POSITION;
                float4 color    : COLOR;
                float2 texcoord : TEXCOORD0;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct v2f
            {
                float4 vertex   : SV_POSITION;
                fixed4 color    : COLOR;
                float2 texcoord  : TEXCOORD0;
                float4 worldPosition : TEXCOORD1;
                UNITY_VERTEX_OUTPUT_STEREO
            };

            sampler2D _MainTex;
            fixed4 _Color;
            fixed4 _TextureSampleAdd;
            float4 _ClipRect;
            float4 _MainTex_ST;
            float4 _MainTex_TexelSize;
        float _Range;

            float _RADIUS;

            float2 _Center;
            float _SliderX;
            float _SliderY;

            v2f vert(appdata_t v)
            {
                v2f OUT;
                UNITY_SETUP_INSTANCE_ID(v);
                UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT);
                OUT.worldPosition = v.vertex;
                OUT.vertex = UnityObjectToClipPos(OUT.worldPosition);

                OUT.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);

                OUT.color = v.color * _Color;
                return OUT;
            }

            fixed4 frag(v2f IN) : SV_Target
            {
                half4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color;

                #ifdef UNITY_UI_CLIP_RECT
                color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);
                #endif

                #ifdef UNITY_UI_ALPHACLIP
                clip (color.a - 0.001);
                #endif
                float2 dis = IN.worldPosition.xy - _Center.xy;
                
                   float width  = _MainTex_TexelSize.z;
                float height  = _MainTex_TexelSize.w;
                float aspectRatio = _SliderX/_SliderY;
                float2 newUv = dis / float2(_SliderX,_SliderY) * 0.5;
                float2 roundCenter =(0.5 - _RADIUS,0.5 - _RADIUS);
                if(aspectRatio > 1)
                {
                    newUv.x *= aspectRatio;
                    roundCenter=  float2(0.5 * aspectRatio - _RADIUS,0.5 - _RADIUS);
                }
                else
                {
                    newUv.y *= 1 / aspectRatio;
                    roundCenter=  float2(0.5 - _RADIUS,0.5 * (1 / aspectRatio) - _RADIUS);
                }

                if(abs(newUv.x)<roundCenter.x || abs(newUv.y)<roundCenter.y )
                {
                    color.a *= (abs(dis.x)>_SliderX) || (abs(dis.y) > _SliderY);
                }
                else
                {
                    if (length(abs(newUv) - roundCenter) < _RADIUS)
                    {
                         discard;
                    }
                    else
                    {
                       
                    }
                }

                
                color.rgb *= color.a;

             


                return color;
            }
        ENDCG
        }
    }
}